From Longman Dictionary of Contemporary EnglishHalloweenHal‧low‧een, Hallowe'en /ˌhæləʊˈiːn◂ $ -loʊ-/ ●●●S3 noun [uncountable]TMCthe night of October 31st, which is now celebrated by children, who dress in costumes and go from house to house asking for sweets, especially in the US and Canada. In the past, people believed the souls of dead people appeared on Halloween. → trick or treat